The State Department has gone into full-blown crisis mode, organizing a round-the-clock effort to coordinate the U.S. government's response to the expanding attacks on U.S. embassies in the Middle East and North Africa.

"The State Department has stood up a 24-hr monitoring team to insure appropriate coordination of information and our response. In addition, our consular team is working with missions around the world to protect American citizens and issue appropriate public warden information," a senior State Department official told reporters Friday afternoon. "We have been monitoring events in the Middle East and North Africa intensively today, and working with our personnel and missions overseas and host governments to strengthen security in all locations and to respond effectively where protests have turned violent," the official said.

The official noted that U.S. embassies in Libya and Yemen have been reinforced with Marine FAST teams and noted that other unspecified measures are being taken to strengthen embassy security around the region. The State Department is working with the governments in Tunisia and Sudan to increase security at the U.S. embassies there as well, the official said.

The U.S. Embassy in Tunis was breached by rioters who replaced the American flag with the black banner of al Qaeda. According to Tunisian state television, at least three Tunisians died when security forces open fire in an effort to disperse the crowd; another rioter was killed in Sudan, Reuters reported.

"The secretary, other department principals, and our ambassadors and charges in the field have been in constant contact with regional leaders, and we appreciate the many public statements that leaders have made in recent days condemning the attack in Benghazi, denouncing violence and calling for calm," the official said.

The White House said in a memorandum to Congress Friday that the Marine FAST teams will be there are long as they are needed but will be limited to the mission of protecting U.S. assets and personnel.

"Although these security forces are equipped for combat, these movements have been undertaken solely for the purpose of protecting American citizens and property. These security forces will remain in Libya and in Yemen until the security situation becomes such that they are no longer needed," the White House memorandum stated.